The present invention relates to a slip-form paver.
In a slip-form paver known from DE-A-23 14 812, which is used for placing a single concrete layer, the concrete paving screed is composed of two halves which are arranged one after the other in the traveling direction and are offset relative to one another in the transverse direction and which can be transversely moved relative to one another to change the placement width. The material hopper and transverse distribution means have also an adjustable width. An adjustable width is accomplished through telescopically extensible transverse members of the support frame, from which the paving screed is suspensed at a fixed height. The concrete paving screed therefore acts as a smoothing screed which is pulled over the concrete without any significant compaction effect.
A self-propelled road finisher according to DE-U-295 14 231 is equipped with a high-compaction screed designed for placing concrete, the screed being dragged by the road finisher with lateral pulling bars and the placement thickness being variable through the inclination of the high-compaction screed (entering angle) relative to the base course.
In a road construction machine known from EP-A-0 217 408, which comprises a wheel chassis on a vehicle chassis and a paving screed trailing behind a transverse distribution device that is arranged on the chassis, bituminous or concrete pavement material is laid without any slip forms. In the operative mode the paving screed is in a floating position relative to the chassis and can be blocked hydraulically in the lifting direction and lowering direction relative to the chassis.
A finisher which is known from DE-U-295 10 058 drags, on its chassis via lateral extension arms, two or more high-compaction paving screeds which are arranged one after the other and with the aid of which concrete pavings of a monolayered or multilayerd structure can be placed.
In a slip-form paver known from U.S. Pat. No. 4,073,592, a first, forwardly open material hopper is arranged in the support frame at the front when viewed in traveling direction, and is provided with vibration means and a first transverse distribution means, and a second material hopper is integrated behind the first one and provided with vibration means and a second transverse distribution means. The first transverse distribution means has arranged therebehind a stripper device which adjusts a first concrete layer without any significant compaction effect to the desired height. A second concrete layer which is processed by a tampering device arranged downstream of the second transverse distribution means and which is finally smoothed by a smoothing screed firmly integrated into the support frame and provided with vibration means is supplied by the second material hopper and placed on the first concrete layer. The smoothing screed is divided in the traveling direction. It is possible to place two layers of concrete with this slip-form paver. However, the achievable compaction of the pavement layers is unsatisfactory.
DE-C-3 114 049 dicloses a high-compaction paving screed for bituminous mixed material wherein at least one compacting bar is provided in traveling direction behind a forwardly positioned tampering device and is vertically acted upon downwardly by drive means which generate swelling force pulses. Since the drive means which generate swelling force pulses are upwardly supported on the whole mass of the paving screed with their reaction forces resulting from the action on the compacting bar and since it is solely the swelling forces that are transmitted to the compacting bar, very high degrees of compaction can be achieved in the top layer. The high-compaction paving screed is designed for bituminous material to be exclusively used in a self-propelled road finisher without any slip form.
Slip-form pavers are used with the moving slip form that shapes the concrete laterally and on the surface to place concrete pavings (monolayered ones consisting of one concrete mixture or two-layered ones consisting of concrete mixtures having different compositions). Slip-form pavers have a serious disadvantage insofar as they lay only slightly compactable concrete and the concrete paving cannot be walked on immediately.
It is the object of the present invention to provide a slip-form paver of the above-mentioned type for placing high-quality concrete pavings that can immediately be walked on.